# How to solve this linear equation $x:y:3=2:1:5$

I am a high school student and need help to solve a linear equation. Could you please give me guidance in solving similar equations like this one, and what I should watch for in this type of assignments?

$x : y : 3 = 2 : 1 : 5$

$3x-y= ?$

• The notation is awkward. I can only imagine that you mean $\begin{bmatrix}x\\y\\3\end{bmatrix}=k\begin{bmatrix}2\\1\\5\end{bmatrix}$. Solve for $k$ by looking only at the third entry: $3=5k$. From there, knowing the value of $k$ you can find the values of $x$ and $y$ similarly and then complete the computations necessary. – JMoravitz Feb 1 '17 at 22:39

$$x : y : 3 = 2 : 1 : 5$$ $$x:2=y:1=3:5$$ $$x=\frac{6}{5},y=\frac{3}{5}$$